(*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

include CCHashSet

module Make (E : ELEMENT) = struct
  include CCHashSet.Make [@inlined] (E)

  let update s e ~f =
    let eo = find s e in
    match (eo, f eo) with
    | None, None ->
        ()
    | Some e, Some e' when e == e' ->
        ()
    | Some _, None ->
        remove s e
    | _, Some e' ->
        insert s e'


  let add s e =
    let change = ref false in
    update s e ~f:(function
      | None ->
          change := true ;
          Some e
      | Some e ->
          Some e ) ;
    !change
end
